This invention relates to electronic postage meter systems and more particularly to an electronic postage meter system settable by means of a remotely generated input device.
Many attempts over the past few years have been made to provide postage meter systems which may be remotely settable. More particularly, it has been considered desirable to have a postage meter system which does not require carrying the postage meter to the Post Office for periodically charging or requiring a postal official to come to the meter location for recharging the meter. Several earlier attempts to provide remotely settable meters are noted in U.S. Pat. No. 3,194,946 to Rabinow, wherein a punched card is placed into a mechanically readable meter for the purpose of charging the postal meter to a desired postal setting. In U.S. Pat. No. 3,716,698 to Simjian, a magnetically readable card is provided for the purpose of recording postage. In both of the systems however, the aspects of security, that is to say the ability to create a falsified card, is too easily overcome for either of these devices to be practical.
Furthermore, modern technology has given rise to the microcomputerized postal meter. An example of such meter will be found in U.S. Pat. Nos. 3,938,095, and 3,978,457, both assigned to the assignee of the present invention. A further example of the use of computerized systems for receiving fixed incremental amounts for recharging over a data link or other remote transmitting device is shown in U.S. Pat. No. 3,792,446. The receipt of the variable amount by means of a remote data link is shown in U.S. Pat. No. 3,792,446. In these latter cases, the problems of security are minimized by virtue of a technique for providing uniquely coded identification signals which cannot be falsified by the user.
In U.S. Pat. Nos. 3,800,284 and 3,860,911, a security system is provided for an electronic lock wherein unlocking combinations are generated by two separate units in a pseudo random manner. In the concept of pseudo random generation, the relationship between successive generated numbers from a pseudo random generator cannot be detected intrinsically from an examination of the numbers themselves. The phrase "pseudo random" is employed only because two separate generators, constructed in the same manner (using the same internal algorithm, for example) will generate the same sequence of random numbers. Using this concept, a secure locking system can be provided wherein an electronic lock is constructed with a key- or card-operated input device, prestored combinations being placed upon the card in accordance with the pseudo random generation concept. In this manner, the remote lock can be provided with a similar pseudo random generator, which upon a match between itself and the key or card being inserted therein, will recharge by adding postage to describing and presenting registers and will advance the generator to the next combination. These concepts are fully described and disclosed in the aforementioned U.S. Pat. Nos. 3,800,284 and 3,860,911, assigned to the assignee of the present invention. By the use of such a unique recognition feature, the security aspect essential to the employment of a remotely settable postage meter may be realized.
In addition, besides the remote charging function, the use of the unique identification code provides certain other features which may be employed by a postal meter system such as described hereinabove. Thus, the use of such a card may be employed not only to charge the meter but to read the current state of the registers internally in a remote meter for the purposes of audit. The postal meter in this fashion provides a unique combinational code indicative of the meter to prevent falsification, along with such features as the date of the audit, verification that the audit data is from a specific meter, and assurance that data has not been falsified. The provision of a unique digital signature on an audit card representative of a remote postal meter thus is an essential feature to the provision of an audit function in a remote meter reading device with high security aspects.
It is therefore the prime object of the present invention to provide a secure electronic microcomputerized postal meter remotely chargeable by means of a user-transported device.
It is a further object of the present invention to provide a microcomputerized postal meter employing a prerecorded card for the purpose of charging the meter in a secure fashion.
It is a still further object of the present invention to provide a microcomputerized postal meter with an audit function, enabling the postal meter to dump the contents of any selected internal register in a unique and cryptic manner onto a user-transportable card.